Bows



March 2, 1965 J. W. DALY BOWS Filed Oct. 17, 1961 3 Sheets-Sheet 1INVENTOR.

John M Da/y BY J. W. DALY March 2, 1965 BOWS Filed Oct.

3 Sheets-Sheet 5 IN V EN TOR John W Da/y United States Patent Thisinvention relates to bows and more particularly to laminated, reflexed,recurved bows.

It is desirable that the increase in force to draw the bow should beless for the final increments of the draw than the initial increments ofthe draw. This results in an upward convex force-draw curve. The reasonis that in such an instance more energy is stored in the bow with nogreater force required to hold the bow at full draw. It is also easierto bring the bow to full draw and to hold it there while sighting.

String slap against the archers wrist is a problem. This is basicallybecause traditionally the handles of the bows are in line with the axesof the bows themselves.

Highly recurved bows are difficult to brace.

In conventional bows there is a tendency for the arrow to fall off thearrow rest.

I have made this invention to improve these qualities and solve theseproblems. As to obtaining an upward convex force-draw curve, I havedeveloped a bow wherein the shape of the unbraced bow is a portion of aspiral with the recurve portion and reflex portion a portion of the samemathematical curve. I have found, also, that a flatter curve will beobtained when a straight piece of the limb is attached to the terminalend of the curve and tangent to it.

Also, to obtain a more convex upward force-draw curve, I have found thatit is better to make the belly of the bow weaker than the back of thebow. I have found this may be done by using laminations of the Samematerial and making the laminations at the belly of the bow thinner thanthe laminations of the back of the bow.

A highly recurved bow as developed by this design is very difficult tobrace. I have solved this problem by providing a bracing strap which islonger than the bowstring. With the bracing strap, the bow may be bracedwhile the bowstring is being nocked.

The handle of my improved bow is placed on the bow extending to the sideand toward the belly of the bow. This permits the bow to be drawn andloosed with the back of the hand up and the palm down. In this positionthe elbow, radius, and ulna along with the wrist bones and metacarpalsare locked in their strongest and most rigid position and, therefore,relieve much of the muscular effort to maintain the bow in the fullydrawn position. Also, it places the wrist to one side and away from thestring to reduce slap.

An object of this invention is to provide a bow wherein a maximum ofenergy is stored within the bow at full draw.

Another object of this invention is to provide a bracing strap so that arecurved bow may be easily braced.

Another object is to provide a bow which is pleasing in appearance.

Another object is to provide a pistol-grip handle extending to one sideof the bow so that the bow may be more easily gripped and remove the armfrom the slap of the bowstring.

A further object is to provide an improved arrow rest on the bow.

A further object is to provide a bow wherein the center of gravity isabout the handle or lower than the handle so that the bow does not tendto rotate in the hand of the archer.

Still further objects are to achieve the above with a bow that issturdy, compact, durable, simple and reliable yet inexpensive and easyto manufacture.

The specific nature of the invention, as well as other objects andadvantages thereof, will clearly appear from the following descriptionand from accompanying drawings, the different views of which are notnecessarily to the same scale, in which:

FIG. 1 is an elevational View of a bow according to this invention in anunbraced position.

FIG. 2 is an elevational view of the bow in the braced position.

FIG. 3 is an elevational view of the bow in the process of being braced.

FIG. 4 is a schematic representation illustrating mathematically thedesign of the bow limb.

FIG. 5 is a sectional view through the bow showing one type oflamination.

FIG. 6 is a sectional view through the limb of the bow showing anotherand preferred type of lamination.

FIG. 7 illustrates the three force-draw curves for bows designedaccording to this invention.

FIG. 8 is an enlarged sectional view illustrating the bowstring nooks,taken on line 88 of FIG. 12.

FIG. 9 is an enlarged sectional view through the arrow rest, taken online 9 of FIG. 11.

FIG. 10 is an enlarged partial elevational view taken from the back ofthe bow illustrating the handle and arrow rest.

FIG. 11 is an enlarged partial view of the mid-section of the bow takenfrom the side illustrating the handle and arrow rest.

FIG. 12 is an enlarged sectional view of the mid-section of the bowtaken from the belly illustrating the hanle and arrow rest.

FiG. 13 is a sectional view taken on line 13-13 of FIG. 10.

FIG. 14 is a sectional view showing a modified means of mounting thehandle.

As may be seen in the accompanying drawings, the bow has a rigidmid-section It with upper limb 12 and lower limb 14 attached to themid-section. The rigid mid-section It would normally be the handle,except in this case the pistol-grip handle 16 is attached thereto. Onthe end of each limb is nock 18 which will be more fully describedlater.

The preferred curve for the limb is a hyperbolic spiral following theformula r0=a. Other likely curves would be the ellipse, cycloid,troehoid, epicycloid, epitrochoid and hypotrochoid. It will berecognized in the formula that a is a constant, 1' is the length of aray from center point 0 to a point on the spiral, and 0 is the anglebetwen said ray and a fixed line through said center point 0 (FIG. 4).

If a is taken to equal 8 inches, a good limb results.

Referring more specifically to FIG. 4, if the center 0 is arbitrarilyplaced in position, the curve will approach a line 8 inches from thecenter. ince the bow is symmetrical with reference to a plane designatedby line 20 through the center of the bow normal to the longitudinal axisof the bow, it will be necessary to describe only one limb 14 as seen inFIG. 4. The center of the spiral was chosen to be 25% inches from theplane of the limb 17 which was straight.

20, and the value of r"was computed for values of from 27 to 150,measured clockwise from a line imately 9 from line 22 which is parallelto line Zil. At 7 0 equal to 27, the line lacks only 1 from being normalto line 20, so it was assumed to be normal at this point. It Wascontinued along at that point for a length of 10 /2 inches until itreached the centralplane (line 20). The midsection 10 extends out forthis distance from the central plane 20 so the curve is discontinued atthat point.

From the above description it may be seen that each limb could bedivided into three areas. The first area adjacent to the rigidmid-section and having a slight curvature away from the belly side ofthe bow. The second area would be that portion of the bow having agreater curvature away from the belly of the bow than the first area.The third area would be that portion from'the description that the rigidmid-section of the bow encompasses that portion of the bow where thecurve as described in FIG. 7 is normal to the center plane 20, and thaton either side of the mid-section, the.

limbs of the bow curve away from the belly side. Therefore, the finishedbow is 70 inches long, tip to tip on the outside. Sixty-nine inches isthe distance be tween bowstring notches 24 in the nocks 18 (FIG.' 8).The rigid mid-section 10 is 21 inches long, i.e. extending 10 incheseither side of the central plane 20.

The cross section of the limbs 12 and 14 is rectangular with uniformthickness throughout. width is tapered from 1% inches at the end of therigid mid-section 10 (10 /2 inches from the central plane 20) to inch atthe base of the nock 18. Ten inches from the end of the rigidmid-section 10 (20 /2 inches from the central plane 20) the width is 1%inches, and 6 inches further out (27 inches from the central plane 20)the width is 1% inches.

The limbs are made of four glass reinforced epoxy laminates. FIGS. and 6illustrate two means by which the epoxy laminates may be placed. In theFIG. 5 two thinner laminae are placed at the back of the bow followed bytwo thicker ones at the belly. Reading progressively from the back thesethicknesses are .040 inch, .050 inch, .060 inch and .060 inch. Theattachment of the limbs 12 and 14 to the mid-section is by any well- Itwill be noted However, the

known means; two of the laminae going to the back of the rigidmid-section 10 and two to the belly. The laminae are arranged in a formhaving desired shape and glued together with any suitable glue.

In FIG. 6 the thinner laminae are placed at the 'belly of the bow.Reading from back to belly, these thicknesses are .060 inch, .060 inch,.050 inch and .040 inch.

Referring now to FIG. 7, the line F5 is the force-draw curve for a bowconstructed according to FIG. 5 and shaped according to FIGS. 1 and 4 asdescribed above. The diagram shows the force in pounds necessary to drawthe bow the number of inches given. The draw in inches in FIG. 7 is thedistance from the belly of the bow to bowstring 26 at the arrow neckingpoint. Therefore, 26 inches on the diagram would correspond to a' 28inch draw if the draw were being measured from the back of the bow assome people do, inasmuch as the bow is 2 inches from back to belly atthe arrow rest.

The line F6 represents a bow constructed with laminations according toFIG. 6 with the thinner laminations at the belly of the bow and thethicker at the back. The line F6 illustrates thebow constructedaccording to FIG. 6; however, in this case, the width of the how was nottapered as described above but was 1% inches from the rigid mid-section10 to the nock 18.

The bow from which the force-draw values for curve F7 /2 were taken wasidentical with the bow of curve 4. F6, untapered, and with the thinnerlaminae on the belly as per FIG. 6, except that the terminal tangentialsegment 17 was made 7 /2 inches long instead of 4 /2 inches long, i.e. 3inches longer than the tangential segment of the bow of curve F6.

More particularly, comparing F5 and F6, it will be noted that these arefor bows of identical width, identical thickness and identicalcurvature, the only difference being that the line F6 is drawn for thebow having thinner laminae on the belly than on the back, whereas theline F5, has thinner laminae on the back than on the belly. Thepotential energies of the bows are represented by the areas beneath thecurves and the terminal ordinates. By comparing curves F5 and F6 tocurves F5 and F6 respectively, it is obvious that a greater amount ofenergy is stored in a bow having a force-draw curve that is convexupwardthan inone of equal terminal weight with a linear force-drawcurve. It is also plain that the area beneathcurve F6" and the terminalordinate is greater than that of thearea bound by .curves F5 and F5 tothe area beneath F5 and theterminal ordinate; thus, the flatter theconvex upward force-draw curve becomes, the greater is the percentage ofstored energy compared to a linear force-draw curve of the same terminaldraw weight. Of course, the belly could be weakened by providing laminaeof different material.

Also, it has been found that an extension of the tangent portions 17near the nocks at the end of the recurve will cause the force-draw curveto be flatter (i.e. more stored energy per total draw). Comparing thearea beneath curve F7 /2 and the terminal ordinate to that below curveF7 /2, it is apparent that the former defines an area nearly 1 /2 timesas great as the latter.

As stated before, the highly recurved bow is difficult to string.Therefore, I have provided bracing strap 28 (FIG. 3). It will beunderstood that the bowstring 26 itself is a conventional one with aneye at either end, the eye of the bowstring fitting in notches 24 of thenock 18 (FIG. 8). The bracing strap 28 is constructed of any stoutmaterial and is long enough to fit into notches30 of the nock 18 whenthe bow is in the relaxed or unbraced position as seen in FIG. 1. Thenotch 24 and notch 30 itle adjacent each other and are near the tip orend of the imbs.

The bracing strap 28 has a long eye at each end. To

brace the bow, the bowstring 26 is placed with one eye within its notch24,'and the bracing strap 28 is placed with both of its eyes in itsnotches 30. Then the archer stands With one foot upon the bracing strap28 and pulls by one hand upon the rigid midsection 10 of the bow (FIG.3). Then with the other hand he guides the other eye of the bowstring 26along the belly of the bow and through the eye of the'ibracing strap 28and into its proper place. Then the bow is lowered so that the bowstring26 has its tension and maintains the bow in braced position (FIG. 2).Thereafter, the bracing strap 28 is removed.

Of course, the bowstring can be operated from the notch 30. I, This.might be desired because the bow then would have .1 differentcharacteristics because the diiferent response of the bow strung fromthis position.

To form the notch 30 on bows having aconventional nock 18 as seen inFIG. 8, it is. possible to place an auxiliary nock 32. The auxiliarynock 32 would be attached to the main nock 18 by gluing and by a pair ofscrews 34. Also, the surface of the original nock 18 could be roughenedor corrugated to mate corrugations: of the auxiliary neck 32 to betterhold it as desired.

' Of course, it is possible to work out other systems by which thebracing strap 28 is attached'to the tip of the bow. The main featurebeing that the bow is braced by a bracing strap which can be attached.to the bow while it is in the unbraced, relaxed position and the bowbraced sufficiently to attach the bowstring.

' Observing the bow from the belly side (FIG. 12), it will be noted thebow is recessed for an arrow rest. It has been found desirable toprovide an arrow plate 36 upon vertical surface 38 of the arrow rest. Iprefer to make this arrow plate from Teflon because this material isparticularly tough and has a very low coeflicient of friction.

Arrow 40 may also rest on the lower side against cone 42 which ismounted for rotation on the spindle 44 about its axis. The spindle 44 isset up into nearly horizontal surface 46 of the arrow shelf. I prefer tomake the cone 42 from nylon because it has high strength for low weight.It will be noted that the angle between the vertical portion 38 and thenearly horizontal portion 46 is greater than 90. The cone chosen for 42is a right-angle conethat is to say the apex angle is 90. The spindle isset into the wood by gluing or otherwise, and the cone is kept in placeby screw 48. Therefore, I have provided an arrow rest offering verylittle friction to movement of the arrow past the bow at this point.Also, the force of gravity acting on the arrow resting on the inner edgeof the cone will prevent it from slipping off the arrow rest.

On the mid-section the pistol-grip handle 16 is attached to the lateralside of the bow (FIGS. 10, 11 and 12). The handle 16 angles downwardfrom vertical. The rigid mid-section ll) of the bow at this point isabout three inches wide from back to belly which is about one inch widerthan the customary width of bows at this point. The bow is originallymade about one inch wider than an ordinary bow at this point, i.e. thatarea 50 on the right side of the bow as seen in FIG. 12 protrudes pastthe normal outline of the bow to provide additional strength because thehandle is recessed into the side of the bow. The distance from belly toback is increased to add additional weight below the center of the bowso that the bow nearly balances as desired. Above the horizontal portion46, the thickness of the bow from back to belly is reduced about twoinches. This reduces the weight above the center of the how.

The handle 16 is similar to a pistol grip and is fashioned to fit thehand. Notches are cut for the little finger and the two adjacent fingersin the butt portion of the handle which is inclined at an angle of 65 tothe plane formed by the string and the central axis of the bow. Anelongated groove 52 is cut for the index finger, and a similar elongatedgroove 54 is cut for the thumb. The handle is cut to a length so thatthe last joint of the index finger can be flexed over the end (FIG. 11).The grooves 52 and 54 are parallel. The elongated position of the indexfinger and thumb gives control of the revolution of the bow and permitsrotating it or provides resistance to undesired rotation in the plane ofthe string and longitudinal center line of the how. The handle is setwith the how so that the anterior portions of the thumb and forefingerare at or beyond the longitudinal center line of the bow. This is forthe purpose of achieving balance and elimination of lateral torque whenthe bow is drawn. The handle is inclined at an angle of 10 to thelongitudinal axis of the bow. Thus, when the arm is extended with theback of the hand up, the palm and fingers gripping the handle, the bowis inclined at an angle of 10 off vertical which inclination allowsgreater vision through the sighting window. Slight rotation of the wristpermits other positions of the bow or the handle can be set at differentangles for this purpose. Of course, the angles given have been found tobe good average positions for the average archer. Other angles could beused to suit individual preferences or custom bows.

The handle is fitted into a channel cut into the rigid mid-section 10and can be located in any position with reference to the belly of thebow either forward or back. This permits designing the bow for any drawlength, either an underdraw or overdraw. Usually, the handle is cementedin a fixed position by suitable material once the draw is decided upon.

'A. modification is shown in FIG. 14 wherein a slot 56 is cut throughthe base of the handle 16 which is also recessed to accommodate the headof the bolt assembly 57. The handle can be moved either forward or backat will and held firmly in the desired position by tightening the wingnut of the bolt assembly 5'7. Another variation would be to mount thebutt of the pistol grip in a ball and socket joint. Then the angle ofthe handle may be changed at the whim of the archer.

The handle is set as closely as possible to the center of gravity of thebow and, if possible, slightly above it.

It will be apparent that the embodiments shown are only exemplary andthat various modifications can be made in construction, materials andarrangement within the scope of the invention as defined in the appendedclaims.

I claim as my invention:

1. In a bow having a rigid mid-section and two resilient limbs attachedto either end of the mid-section, and a string connecting the extremeends of the limbs, the improvement comprising: said limbs beingconstructed to be a portion of a spiral when the bow is in the unstrungcondition, said spiral following the general formula of r9=a, wherein ais a constant, r is the length of a ray from a center point to a pointon the spiral, and 0 is the angle betwen said ray and a fixed linethrough the center point.

2. The invention as defined in claim 1 with the addition of a handleattached to a lateral side of the midsection of the bow, said handleextending generally to the side of the bow, said handle angling downwardfrom the horizontal when the axis of the bow is vertical, said handleangling backward toward the string.

3. The invention as defined in claim 1 wherein the tip of the limb is astraight section tangent to the spiral at that point.

4. The invention as defined in claim 1 wherein there are two notchesadjacent the tip of each limb, one notch adapted to receive thebowstring, the second notch adapted to receive a bracing strap.

5. The invention as defined in claim 1 wherein the limbs are constructedof layers of material and the layers toward the belly of the bow areweaker than the layers toward the back of the how.

6. The invention as defined in claim 5 wherein the limbs are laminatedand the lamina near the belly of the bow are thinner than the laminanear the back of the bow.

7. A bow comprising: an upper and lower limb attached together, a notchat the tip of each limb, a bowstring with an eye at each end, one eye ineach notch, a second notch adjacent the first mentioned notch of eachtip, and a strap attached at each end to each second notch, said strapbeing longer than the bowstring; so arranged and constructed that thebow may be braced by the strap while nocking the bow string.

8. A how comprising: an upper and lower limb attached together, a notchat the tip of each limb, a bowstring with an eye at each end, one eye ineach notch, a strap longer than the bowstring, and means for attachingeach of the ends of the strap to each of the tips of limbs, said strapso attached; so arranged and constructed that the bow may be braced bythe strap while necking the bowstring.

9. The invention as defined in claim 8 with the addition of a handleattached to a lateral side of the midsection of the bow between theupper and lower limb, said handle extending generally to the side of thebow, said handle angling downward from the horizontal when the axis ofthe bow is vertical. and said handle angling backward toward the string.

10. A bow comprising: a rigid mid-section, two resilient limbs attachedto either end of the mid-section, and a string connecting the extremeends of the limbs; said limbs being made of four glass reinforcedlaminas, the

two laminas at the back being thicker than the two lami mates of thebelly and the lamina to the extreme belly side being thinner than thebelly lamina adjacent the back laminate. a

References Cited by the Examiner UNITED STATES PATENTS 1 OTHERREFERENCES C. N. Hickman, Forest Nagler, Paul E. IGopstegrArchery: TheTechnical Side, First Edition, National Fiel Archery Assoc, 1947, page62, FIG 4a.

JAMES W. LOVE, Examiner.

LOUIS R. PRINCE, Primary Examiner.

1. IN A BOW HAVING A RIGID MID-SECTION AND TWO RESILIENT LIMBS ATTACHEDTO EITHER END OF THE MID-SECTION, AND A STRING CONNECTING THE EXTREMEENDS OF THE LIMBS, THE IMPROVEMENT COMPRISING: SAID LIMBS BEINGCONSTRUCTED TO BE A PORTION OF A SPIRAL WHEN THE BOW IS IN THE UNSTRUNGCONDITION, SAID SPIRAL FOLLOWING THE GENERAL FORMULA OF R0=A, WHEREIN AIS A CONSTANT, R IS THE LENGTH OF A RAY FROM A CENTER POINT TO A POINTON THE SPIRAL, AND 0 IS THE ANGLE BETWEEN SAID RAY AND A FIXED LINETHROUGH THE CENTER POINT.